In recent years, a mechanism has been becoming popular in which a terminal set at a specific place (e.g. digital signage terminal) or a tag including a short-distance radio communication function (e.g. near field communication (NFC) tag) and a communication device possessed by a user carry out communications and thereby some kind of service is provided to this user. In this mechanism, by success in the communications between the terminal or tag and the communication device, the existence of this communication device in the radio communication range of the terminal or tag is proved. That is, this mechanism can provide some kind of service to the user of the communication device whose existence in a specific place or range is authenticated. Besides the case in which the communication device and the terminal or tag carry out short-distance radio communications, there is also the case in which the communication device reads information on the terminal or tag by using a camera or the like and thereby some kind of service is provided similarly.
For example, a service is known in which a visit of a user to a shop is authenticated and a privilege (point or coupon) that can be used in the shop is given to the user through reading of a quick response (QR) code (registered trademark) displayed on a terminal set in the shop by a communication device possessed by the user.
Furthermore, a grouping system that groups plural communication devices is known (for example, Japanese Laid-open Patent Publication No. 2015-65521). First, the plural communication devices acquire a unique identification (ID) from an NFC tag including the unique ID and transmit the acquired unique ID to a server. When receiving the unique ID from the plural communication devices, the server sets the communication devices that have transmitted the same unique ID as the same group. For example, this grouping system distributes the same information to the grouped communication devices.